Overload-release clutch



Junev20, 1933. w A, 'ANDRES I 1,914,795

OVERLOAD RELEASE CLUTCH Filed Sept. 25.," 1951 II' I 50 ing means in driving relation.

Patented June 20, 1933 UNITED STATES PATENT carica A.. ANDRES, OF BRIDGEPOBT, CONNECTICUT, .ASSIGNOB T TEE SINGER MANUFACTURING COMPANY, 0F ELIZABETH, NEW JERSEY, A GORPOBTION 0F NEWJEBSEY ovnnLoAn-nnnnasn cnu'rcn .ippneanen mea september 25, 1931. serial ne. 585,017.

This invention relates to overload-release clutches, and has for its primary object to provide simple and eiective means automatically operative when a predetermined load or torque is applied to the driven element, to disconnect the driven element, and thereby prevent undue strain and possible injury to the mechanism.

A vfurther object of the invention is to pro- 1 vide improved means for re-connecting the driving element to the driven element after it has been disconnected therefrom. Another object of the invention is to provide improved adjustable means for redetermining the maximum torque desire to be imparted to the driven element.

Another object of the invention is theprovision of an improved clutch which will autoconnecting the driven and driving elements is urged to disconnected position after it has been partially disengaged.

Another object of the invention is to provide improved means 'for moving the lmember connecting the driven and driving elements to an ineiective position out of contact with the driven member.

' With the above and other objects in view, as will hereinafter appear, the invention consists in the devices, combinations, andarrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features ofthe invention and the advantages attained thereby will be readily understood by those skilled inthe art.

*In the accompanying drawing: y

l Fig. 1 is an end view showing the connect- ,i

ing means in disengaged position.

Fig. 3 is a section on the line H of Fig. 2.

In the embodiment of this invention .selected for illustration, 1 is the driving element in the present instance in the form of a pulley adapted to be driven from any suitable source of power, and the shaft 2 represents the driven element on which the driving element is rotatably supported. 1t will be obvious that these parts may beinterchanged or thatother forms of power transmissionelements may be substituted for yeither or both of them.

Abutting one edge of the hub of the driving element 1 is a collar 3 fixed to the shaft 2 by -means of set screws 4. On the opposite side of the hub of the driving element and abutting it is another collar 5 fixed to the shaft 2 by any suitable means, shown in this embodiment as .set screws 6. The driving element is confined against longitudinal movements upon the shaft between these two collars. The collar 5 has a recess 7 with inclined sides, and a shoul` y dered recess 8 in the periphery thereof.

Pivotally secured at one end by a screw 10 tothe face. of the driving element is a link 9, which is provided with a wedge-shaped projection 11, adapted to enter the recess 7 in the collar 5. The other end of the link 9 is pivotally connected by the screw 12 to a second link 13. The opposite end of the link 13 is pivoted to the bow or arcuate spring 15 which is adjustably secured to the face of the driving element 1 by means of the screw- 16 andthe elongated slot 17. The extreme end 18 of the bow spring 15 is bent to form an angle of with the body of the spring 15 and extends downwardly into the radially arranged channel 19 to positively hold the spring against any tendency to rotate about the pivot screw 16 and also toreduce the strain onV the said screw.

` To break the toggle and rie-establish driving relation apawl 21 is pivotally mounted `at 2() upon the toggle link 9 adjacent the pivotal connection thereof. The pawl 21 is adapted ,to engage the shouldered recess 8 in the periphery of the collar 5.' A light spring `23 which is secured by thestud 22 to the face 39 Fig. 2 is an end view showing the connect i s in Fig. 2.

The stud 22 acts as a stop for the link 9 when the toggle is in disengaged position, as shown Operation l `The driving element 1 is driven in the direction indicated by the arrows in Figs. 1 and 2. When an excessive load or torque 1 is applied to the element A2 the wedge-shaped projection 11 is forced out of the recess 7 in/` the collar 5 by the .inclined wall, thereby aligning the pivot points and straightening the toggle', as shown in Fig. 2. Preferably, suicient momentum is given the toggle when it is straightened to cause a sli ht reverse bending thereof, which is limitedy the stud 22. The e'ect of this slight reverse bendin of the toggle is to move the wedge-shape projection on the link y9 to a position out of Contact with the collar 5, as shown in Fig. 2. When the wedge-shaped projection 11 on the link 9 is moved to a position out of contact with the collar 5, the spring-pressed pawl 21 which is pivoted to the toggle link 9 is -moved outwardly with the link 9, and the free end of the pawl rides freely over the periphery of the collar 5 in a counter-clockwise direction as long as the driving member overruns the driven member 2. It will be observed that the bow spring acts in the d irection of the iixed pivot 10 of the toggle link 9, the spring, therefore, tends to break the toggle both inwardly and outwardly. It will be obvious that the maximum force required to straighten the toggle is at the beginning of the straightening operation, dimmishing as the pivot points approach alignment. i

When it is desired to re-establish driving relation, the driving element is rotated inv the reverse direction. When the shouldered recess 8 Ain the collar 5, enga es thel pawl 21 which is urged inwardly by tie light spring 23, the pivotal polnt 12 of the toggle is Avpulled inwardly, breaking the toggle and thereby forcing the projection 11 on the link collar 5. l

In the preferred embodiment of the invention the shoulder 8 and the recess 7 are so spaced circumferentially on the collar 5 that the wedge-shaped projection 11 on the link 9 is in a position to directly enter the recess'.- 7 when the pawl 21 acts to break the togglev inwardly.

From the foregoing description considered in connection with the accompanying drawing, the construction, manner yof operation and several advantages of my improved overload-release clutch 'will be clearly and fully v understood. It is apparent that such a device *s 'a wide variety of uses, and. it will be um.. lstood that the form, constructlon and arrangement of the several elements ernployed may be varied. Therefore, the riviege is reserved of resorting to all such egxtlmate chan es therein as may be fairly embodied 'wiiin the spirit and scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is 1. An overload-release clutch comprising a rotatable driving element, a rotatable driven element, means for connecting said driving and driven elements, means for moving said connecting means to an inactive position when a predetermined load is applied to said driven element, and a pawl under control of said driven element for thereafter moving said connecting means to its active position.

2. The combination of rotatable driving and driven elements, means connecting said elements comprising members pivoted to form a toggle joint, and a bow spring pivoted to one of said members for breaking said toggle joint when the pivot points are not in alignment. l

3. The combination of rotatable-driving and driven elements, means for maintaining said elements in driving relation comprising members pivoted to form a toggle joint a bow spring pivoted to one of said membersfor breaking said toggle joint when the pivot points are not in alignment, and means for predeterminng the force required to allgn said pivot points against the action of said ring. N

4. The combination of rotatable driving and driven elements, a toggle joint for con; necting said elements in driving relation, said toggle joint comprising a link having one end pivotally secured to one of said elements and provided with a projection adapted to enter a recess with an inclined side in the other of said elements, a second link pivoted to the free end of the rst mentioned link, and apbow spring pivotally connected to said second link, said bow spring being adjustably secured to said first mentioned element and acting in a direction towards the 9 into the Wedge shaped recess 7 in the fixed pivotal-axis of the first mentioned link.

5. In a device of the class described in combination, rotatable driven and driving elements, av toggle joint adapted to maintain driving relation between said elements when said toggle joint is broken, means for straightening said toggle joint when an ab- Y normal load is applied to oneof said elements, and means for thereafter breaking the toggle and re-establishing driving relation upon reverse rotation of either element.

6. An overload-release clutch comprising, rotatable driving and driven elements, a yielding'` connection between said elements, said connection comprising a toggle having one end pivoted to one ofV saidvvelements, and a resilient member pivoted to lthe' other4 end of said toggle, means for frendering*s'ai d nection ineective when an abnormal load is aglied to one of said elements, and means for ereater rendering said connection effective by reverse rotation of one of said elementa.

- 7.An overload-release clutch com rising,

a rotatable drivin element, a rotatab e driven element, a ie ding to gle joint carried by one of said e ements an engaging the other of said elements to connect said elements in driving relation, means for moving said toggle joint to an inactive position when an abnormal load is yapplied to one of said elements, and means for thereafcer moving said is togge joint to its active T`position by reverse rotation of one of said elements.

8. An overload-release einfach com rising, rotatable driving and driven mem rs, a yielding toggle device c'rried by one of said members, an element o said toggle device and the other of said members having interenga ing walls which coact to straighten the togg e and disengage said walls under an .overload condition 1n a given direction of rotation, and means for automatically breaking said toggle upon reverse rotation of one :of said'members, said means including a awl .carried by said toggle device and a paw actuator carried bythe other of said members,

33` A In testimony whereof I have signed my ,name to this s ification.

A. ANDRES. 

